1. Field of the Invention
This invention relates to a torch angle setting apparatus advantageously used in a cutting apparatus carrying out a mold cutting while forming a bevel with respect to a material to be cut.
2. Description of Related Art
When figures having straight lines or curves are cut out from a material to be cut such as a steel plate or a stainless steel sheet or the like by using a torch, for example a gas cutting torch or a plasma cutting torch, a moving route of the torch is controlled so as to make the moving route an edge line of the desired figure, and a mold cutting has been carried out by driving the torch during this moving process. A cutting apparatus for carrying out the mold cutting includes a running cart running in the Y-axis direction along a laid rail and a transverse cart, equipped with the torch and mounted on the running cart, moving transversely in a direction perpendicular to the direction of the laid rail (X-axis direction), and the cutting apparatus is so constructed that the moving speed and moving direction of the torch can be controlled by controlling the speed and direction of the respective carts.
With regard to the moving control of the running cart and the transverse cart, a numerical control (NC) apparatus or a tracing apparatus which optically traces an edge line of a template may be used. In particular, a large cutting apparatus is generally constructed as an NC cutting apparatus in which an NC apparatus controls the moving of the respective carts according to the shape of the figure to be cut as well as the progress of the cutting program including the progress of the cutting process.
When welded to another product, a product, having been cut out from the material to be cut, may form a bevel around the outer periphery. In the case of carrying out the bevel cutting, it is required to control, at any time, an inclining direction of a torch to the normal direction with respect to the progressing direction of the cutting, while controlling to incline the torch according to the desired bevel angle. As a result, it is required for the mold cutting to swing the inclined torch according to the change of the progressing direction of the cutting.
Therefore, the mold cutting apparatus has a bevel cutting apparatus constituted of a torch block constructed so as to set the torch to the desired angle, a torch swinging apparatus swinging the torch block, a torch revolving apparatus revolving the torch accompanied by the swing of the torch block, where it is so constructed as to allow the product to have a bevel with the desired angle at its side surface by controlling the torch swinging apparatus according to the cutting progress.
In the above-mentioned bevel cutting apparatus, the axis of the torch is on the extension line of the swinging axis of the torch swinging apparatus when the torch is in a state vertical with respect to the surface of the material to be cut. The center of the pivotally rotation of the torch is set on the extension line of the axis of the torch when the inclination of the torch is carried out, and the intersection between the extension line of the axis of the torch and the extension line of the swinging axis is so adjusted to be on the surface or on the designated point in the depth direction of the material to be cut.
In the case where a gas cutting torch is used as a torch, the torch connects to hoses for supplying cutting oxygen, preheating oxygen and fuel gas, and in the case where a plasma cutting torch is used as a torch, the torch connects to hoses for supplying plasma gas, hoses for supplying and delivering cooling water, and cables for electricity. Thus, in a space formed between the torch and the torch swinging apparatus, there exist various types of hoses and cables, and therefore, when the torch block is swung according to the progressing direction of the cutting, the weight of the hoses and cables may become resistance, thereby forming notches on the cutting surface. In addition, the range of the swinging angle is limited since the hoses and cables twist, so the rotary chambers for relaying gas fluid or water, or slip rings for electricity are disposed for the purpose of dealing with the hoses or cables smoothly in swinging the torch.
In the torch swinging apparatus as mentioned above, the swinging axis and the axis of the torch are arranged in plane in the normal direction with respect to the progressing direction of the cutting. Thus, a variety of the hoses and cables exist on the swinging axis, and this raises a problem where it becomes difficult to deal with those hoses and cables smoothly. In particular, in accordance with the number of fluids for supplying the torch such as gas, water, or the like and the number of the cables to be connected, the structure of the torch swinging apparatus becomes complicated, so there are raised such problems as making the apparatus larger, increasing cost, or making the maintenance complicated.